Nylon timer



April 26, 1960 G. MOUNTJOY uvvmrox United States Patent Of ice This invention relates to a -fuze arming device, and more particularly to a delay arming device for a fuze em- Patented-Apr. 26,-r1960 '2 tained in an unbalanced inertial relation with respectto theaxis of rotation thereof about the pivot pin 14. j Slideably disposed within recess 19, which is in abutment with recess 13, is an inertial locking member 21 having a protuberance or detent of reduced cross section 22formed thereon. The member 21 is adapted to be urged inward! ly toward the rotor 15 by the action of spring 23 where-; by the extension or detent 22 is seated within a peripheral recess 24 of the rotor.

, It will be understood that the spring pressed member 21 will maintain the rotor 15 locked in an initial, or unarmed, position whereby the detonator 17 will be maintained out of alignment with a lead-in charge, or flash channel 25 providedin casing 11, as shown more clearly on .Fig. 1. The inertial member 21 will maintain the rotor 15 locked in its initial position until the speed of ployed in a spin type ordnance vehicle, such, for example,

as a projectile, missile, rocket or the like.

Although delay arming andsafety devices are well known to those versed in the ordnance fuze art and a large number of such devices have been heretofore de'- vised and have performed satisfactorily, all of theseqdevices have required the occupation of considerable space in the fuze and have been comparatively expensive. Additionally, some of the heretofore devised and utilized devices, such as clock timing devices, have not functioned entirely satisfactorily due to the -difliculty of making the necessary adjustments to the complicated mechanisms contained therein by unskilled field personnel.

Accordingly, one object of the present invention is to provide an arming and safety device which is economical to manufacture and which occupies a minimum of space.

Another object of the present invention is to provide a novel safety and arming device requiring less criticalrnaterials and manpower to manufacture than heretofore realized.

A further object of the present invention is to provide a new delay arming device wherein the period of delay may be readily and quickly varied.

A still further object of the present invention is toprovide a novel simple and compact delay arming mechanism for use in an ordnance fuze.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. 1 is a plan view of the safety and arming device of the present invention in an unarmed position;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a plan view of the device of Fig. 1 in an armed position; and,

Fig. 4 is a plan view of a modified arrangement of the device of Fig. 1.

Referring now to the drawing wherein like reference numerals indicate like parts throughout the several views, and more particularly to Figs. 1 and 2 whereon the safety and arming device for a rotating projectile according to the present invention is indicated generally by the refer ence numeral 11. As shown thereon, the device comprises a casing 12 composed of any material suitable for the purpose such, for example, as steel, brass, or the like, and having an annular recess 13 formed therein. Disposed within the recess 13 by means of pivot pin 14 is a rotor or turret 15 composed of any material suitable for the purpose such, for example, as brass, or the like, and having an opening 16 extending therethrough, the rotor 15 being adapted to have rotative movement therein. Arranged within the opening 16 is a detonator, or a portion of an explosive train 17. An aperture, or recess,'18 is provided within the rotor whereby the rotor is gainrotation of the projectile, wherein the safety and arming device 11 is disposed, has reached a predetermined magnitude whereupon the member 21 will tend to move out: wardly in response to centrifugal force and withdraw ex tension 22 from recess 24. Upon withdrawal of detent 22 from recess 24, the rotor is released forrotative movement until the cord 26 secured to the rotor 15 and casing 11- by means of clamping members 27 and 28 respectively, engages the heater, or filament, wire 29 of tungsten, or the like, extending between electrodes 31 and 32. The cord 26 may be composed of any material suitable for the purpose such, for example, as nylon, cotton, or the like. In order to ensure engagement of the cord 26 with the filament wire 29, electrode 32 is disposed within a well 33 formed within the casing, and electrode 31 is maintained in an elevated position above the casing 11 by means of insulated vertical member 34, as more clearly shown in Fig. 2.

Electrical energy is provided for the heater 29 by battery 35 connected to the electrodes 31 and 32 through leads 36, 37 and set back, or spin actuated switch 38. As shown in Fig. l, the electrical circuit from lead 37 to base electrode 32, which electrode may be a blot of solder within the well 33 is completed, through the casing 11 and terminal 39 secured thereon. It should be apparent therefore that cord 26 will restrain the rotational movement of the arming rotor 15 to the armed position shown on Fig. 3 until the hot wire, or heater, 29 melts, or burns through-the cord in engagement therewith. As shown in Fig. 3, upon severance of the cord 26, the rotor will rotate within the recess 13 until the rotor abuts stop pin 41, whereupon the detonator 17 will be in alignment with the flash channel 25.

In the event that a more prolongeddelay arming time is desired than obtainable by the use of one cord 26, a plurality of timing cords of different lengths, as shown in Fig. 4 may be employed. In this arrangement the rotor would not be released to an armed position until each cord successively engaged the heater 29 and was melted through.

In summary, it should be apparent that the delay arming device according to the present invention provides a compact, versatile and inexpensive device readily adaptable for mass production techniques and which is capable l. A delay arming device comprising a casing, an arming rotor releasably locked within said casing in an initial safe position, means including a spring actuated detent 3 for locking said rotor in said initial safe position and for releasing said rotor therefrom in response to a predetermined value of centrifugal force, threadlike filamentary means loosely interconnecting said rotor and said casing for restricting rotative movement of said rotor upon release of the first named means therefrom, andelectrore sponsive means fixedly secured to said casing in the path of travel of said interconnecting means as said rotor rotates subsequent to the release thereof for effecting severance of said threadlike filamentary interconnecting means upon engagement therewith, thereby enabling said arming rotor to rotate to an armed position.

2. A delay arming'device for a spin type ordnancelvehicle comprising a casing, an arming rotor releasably locked within said casing in an initial safe position and adapted to be rotated to an armed position, means including a spring actuated detent arranged within said casing for locking said .rotor in said initial safe position and for releasing said rotor for rotative movement in response to a predetermined value of centrifugal force acting upon said casing, threadlike filamentary means loosely interconnecting said rotor and said casing for restricting rotative movement of said rotorupon release of the first named means therefrom, and electroresponsive means fixedly secured to said casing in the path of travel of said interconnecting means as said rotor rotates subsequent to the release thereof for severing said for severing said threadlike filamentary interconnecting means in response to engagement therewith thereby enabling said arming rotor to rotate to said armed position.

3. A delay arming device according to claim 2 wherein said arming rotor includes a weighted element for enhancing the rotative movement thereof in response to centrifugal force.

4. A delay arming device according to claim 2 wherein said threadlike filamentary interconnecting means includes a nylon cord having a predetermined length and diameter.

5. A delay arming device according to claim 2 wherein said electroresponsive means includes a heater Wire and a potential energy source operatively connected thereto for heating said wire.

6. A delay arming device according to claim 5 wherein said electroresponsive means further includes an initially interrupted switch adapted to'be selectively rendered uninterrupted.

Refercnces Cited in the file of this patent UNITED STATES PATENTS 2,458,470 Hafstad an. 4, 1949.

2,485,817 Dike Oct. 25, 19.49

2,773,449 Karsberg Dec. 11, 1956 2,775,942 Dell Jan. 1, 1957 FOREIGN PATENTS 606,474 Great Britain Aug. 13, 1948 

